The present invention relates to agricultural implements in general, and more particularly to improvements in agricultural implements of the type wherein one or more driven knives are used to treat the material of the ground.
German Offenlegungsschrift No. 18 00 229 discloses an agricultural implement which treats the ground with several flat blade-like knives. The knives are mounted in such orientation that their planes are inclined relative to the tangents of circles which are described by the knives. Each knife serves for individual loosening of a piece of the ground and is intended to cut and break up vegetable matter in the ground.
A drawback of the implement which is disclosed in the German publication is that vegetable matter and soil tend to accumulate on the knives so that the knives must be cleaned at frequent intervals if the implement is to remain operative. Furthermore, the holder for the knives extends from the housing and prevents accurate guidance of the implement in a desired direction. Larger implements of the just described type employ several rotary knife holders which are driven to rotate in opposite directions. This causes the knives to jam when they strike upon relatively large and hard obstructions, such as pieces of rock or the like.